You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
tdegraphics/kviewshell/plugins/djvu/libdjvu/DjVuFileCache.cpp

273 lines
7.6 KiB

//C- -*- C++ -*-
//C- -------------------------------------------------------------------
//C- DjVuLibre-3.5
//C- Copyright (c) 2002 Leon Bottou and Yann Le Cun.
//C- Copyright (c) 2001 AT&T
//C-
//C- This software is subject to, and may be distributed under, the
//C- GNU General Public License, Version 2. The license should have
//C- accompanied the software or you may obtain a copy of the license
//C- from the Free Software Foundation at http://www.fsf.org .
//C-
//C- This program is distributed in the hope that it will be useful,
//C- but WITHOUT ANY WARRANTY; without even the implied warranty of
//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
//C- GNU General Public License for more details.
//C-
//C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library
//C- distributed by Lizardtech Software. On July 19th 2002, Lizardtech
//C- Software authorized us to replace the original DjVu(r) Reference
//C- Library notice by the following text (see doc/lizard2002.djvu):
//C-
//C- ------------------------------------------------------------------
//C- | DjVu (r) Reference Library (v. 3.5)
//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved.
//C- | The DjVu Reference Library is protected by U.S. Pat. No.
//C- | 6,058,214 and patents pending.
//C- |
//C- | This software is subject to, and may be distributed under, the
//C- | GNU General Public License, Version 2. The license should have
//C- | accompanied the software or you may obtain a copy of the license
//C- | from the Free Software Foundation at http://www.fsf.org .
//C- |
//C- | The computer code originally released by LizardTech under this
//C- | license and unmodified by other parties is deemed "the LIZARDTECH
//C- | ORIGINAL CODE." Subject to any third party intellectual property
//C- | claims, LizardTech grants recipient a worldwide, royalty-free,
//C- | non-exclusive license to make, use, sell, or otherwise dispose of
//C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the
//C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU
//C- | General Public License. This grant only confers the right to
//C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to
//C- | the extent such infringement is reasonably necessary to enable
//C- | recipient to make, have made, practice, sell, or otherwise dispose
//C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to
//C- | any greater extent that may be necessary to utilize further
//C- | modifications or combinations.
//C- |
//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY
//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF
//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
//C- +------------------------------------------------------------------
//
// $Id: DjVuFileCache.cpp,v 1.9 2004/08/06 15:11:29 leonb Exp $
// $Name: release_3_5_15 $
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#if NEED_GNUG_PRAGMAS
# pragma implementation
#endif
#include "DjVuFileCache.h"
#include "debug.h"
#include <stdlib.h>
#ifdef HAVE_NAMESPACES
namespace DJVU {
# ifdef NOT_DEFINED // Just to fool emacs c++ mode
}
#endif
#endif
DjVuFileCache::~DjVuFileCache(void) {}
int
DjVuFileCache::Item::qsort_func(const void * el1, const void * el2)
{
const Item * item1=*(Item **) el1;
const Item * item2=*(Item **) el2;
time_t time1=item1->get_time();
time_t time2=item2->get_time();
return time1<time2 ? -1 : time1>time2 ? 1 : 0;
}
void
DjVuFileCache::set_max_size(int xmax_size)
{
DEBUG_MSG("DjVuFileCache::set_max_size(): resizing to " << xmax_size << "\n");
DEBUG_MAKE_INDENT(3);
GCriticalSectionLock lock(&class_lock);
max_size=xmax_size;
cur_size=calculate_size();
if (max_size>=0) clear_to_size(enabled ? max_size : 0);
}
void
DjVuFileCache::enable(bool en)
{
enabled=en;
set_max_size(max_size);
}
void
DjVuFileCache::add_file(const GP<DjVuFile> & file)
{
DEBUG_MSG("DjVuFileCache::add_file(): trying to add a new item\n");
DEBUG_MAKE_INDENT(3);
GCriticalSectionLock lock(&class_lock);
// See if the file is already cached
GPosition pos;
for(pos=list;pos;++pos)
if (list[pos]->get_file()==file) break;
if (pos) list[pos]->refresh(); // Refresh the timestamp
else
{
// Doesn't exist in the list yet
int _max_size=enabled ? max_size : 0;
if (max_size<0) _max_size=max_size;
int add_size=file->get_memory_usage();
if (_max_size>=0 && add_size>_max_size)
{
DEBUG_MSG("but this item is way too large => doing nothing\n");
return;
}
if (_max_size>=0) clear_to_size(_max_size-add_size);
list.append(new Item(file));
cur_size+=add_size;
file_added(file);
}
}
void
DjVuFileCache::clear_to_size(int size)
{
DEBUG_MSG("DjVuFileCache::clear_to_size(): dropping cache size to " << size << "\n");
DEBUG_MAKE_INDENT(3);
GCriticalSectionLock lock(&class_lock);
if (size==0)
{
list.empty();
cur_size=0;
} else
if (list.size()>20)
{
// More than 20 elements in the cache: use qsort to
// sort them before picking up the oldest
GTArray<void *> item_arr(list.size()-1);
GPosition pos;
int i;
for(pos=list, i=0;pos;++pos, i++)
{
GP<Item> item=list[pos];
item->list_pos=pos;
item_arr[i]=item;
}
qsort(&item_arr[0], item_arr.size(), sizeof(item_arr[0]), Item::qsort_func);
for(i=0;i<item_arr.size() && cur_size>(int) size;i++)
{
Item * item=(Item *) item_arr[i];
cur_size-=item->get_size();
GP<DjVuFile> file=item->file;
list.del(item->list_pos);
file_cleared(file);
if (cur_size<=0) cur_size=calculate_size();
}
} else
{
// Less than 20 elements: no reason to presort
while(cur_size>(int) size)
{
if (!list.size())
{
// Oops. Discrepancy due to an item changed its size
cur_size=0;
break;
}
// Remove the oldest cache item
GPosition oldest_pos=list;
GPosition pos=list;
for(++pos;pos;++pos)
if (list[pos]->get_time()<list[oldest_pos]->get_time())
oldest_pos=pos;
cur_size-=list[oldest_pos]->get_size();
GP<DjVuFile> file=list[oldest_pos]->file;
list.del(oldest_pos);
file_cleared(file);
// cur_size *may* become negative because items may change their
// size after they've been added to the cache
if (cur_size<=0) cur_size=calculate_size();
}
}
DEBUG_MSG("done: current cache size=" << cur_size << "\n");
}
int
DjVuFileCache::calculate_size(void)
{
GCriticalSectionLock lock(&class_lock);
int size=0;
for(GPosition pos=list;pos;++pos)
size+=list[pos]->get_size();
return size;
}
void
DjVuFileCache::del_file(const DjVuFile * file)
{
DEBUG_MSG("DjVuFileCache::del_file(): Removing an item from cache\n");
DEBUG_MAKE_INDENT(3);
GCriticalSectionLock lock(&class_lock);
for(GPosition pos=list;pos;++pos)
if (list[pos]->get_file()==file)
{
GP<DjVuFile> file=list[pos]->get_file();
cur_size-=list[pos]->get_size();
list.del(pos);
file_deleted(file);
break;
}
if (cur_size<0) cur_size=calculate_size();
DEBUG_MSG("current cache size=" << cur_size << "\n");
}
GPList<DjVuFileCache::Item>
DjVuFileCache::get_items(void)
{
GCriticalSectionLock lock(&class_lock);
return list;
}
void
DjVuFileCache::file_added(const GP<DjVuFile> &) {}
void
DjVuFileCache::file_deleted(const GP<DjVuFile> &) {}
void
DjVuFileCache::file_cleared(const GP<DjVuFile> &) {}
#ifdef HAVE_NAMESPACES
}
# ifndef NOT_USING_DJVU_NAMESPACE
using namespace DJVU;
# endif
#endif